Online Detection is used to detect the online status of the WAN port, and it is a feature mainly used together with Link Backup. This article mainly introduces how to configure Online Detection as different working mode for different requirements. If you have any other problems about how to configure Link Backup, please refer to FAQ2133.

Online Detection

Go to Transmission > Load Balancing > Online Detection on the web management interface, then you could configure this feature based on the WAN port.

For each port, you could choose one of the three working mode, Auto, Manual or Always Online.

And they will be introduced in the following article.

Auto

In Auto mode, Router would send DNS Lookup packets to the DNS Server of the WAN port automatically. The DNS Lookup packets traverse many famous domains, such as www.google.com, then the DNS Server of the WAN port shall make Domain Resolution for these domains and sent back the results. As long as the Router receive any one of the IP address resolved from these domains by the DNS Server, the WAN port would show as Online. Otherwise, the WAN port would show as Offline.

Note: In this mode, the Ping and DNS Lookup tab is marked as grey that cannot be configured. This verify is not only the connection between the Router and the DNS Server of the WAN port but the Domain Resolution that the DNS Server shall make for the Router.

Manual

In Manual mode, Router would send both Ping and DNS Lookup packets to the DNS Server of the WAN port manually. Here manually means you can configure the destination IP address for Ping and DNS Lookup in these two tabs by yourself. Once the Router receives any reply packets for either Ping or DNS Lookup, the WAN port would show as Online. Only when the Router neither receives neither Ping nor DNS Lookup reply, the WAN port would show as Offline.

Note: If you configure 0.0.0.0 in the tab of either Ping or DNS Lookup, it means you have disabled this detection, and the status of the WAN port would only be verified by the other detection.

Always Online

In Always Online mode, the status of the WAN port will always show as Online, no matter the configuration and connection of it.

Note: In this mode, the Ping and DNS Lookup tab is marked as grey that cannot be configured.

Afterwards

Normally if you want to configure Online Detection to work with Link Backup, you could just enable it, and it would work on Auto mode by default. While as for other special requirements, you could configure it as Manual or Always Online mode by yourself.